Chevy Venture losing reverse

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  #1  
Old 05-31-05, 08:05 AM
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Chevy Venture losing reverse

Hello all. Lately when you put the gear selector in reverse on the wife's van it seems to hesitate before it engages. Its strange because it doesn't seem to do it everytime, it seems to be a random thing.?? Of course she drives it a lot more than I do and I'm only going on her word, but, the other day I did drive it and it did hesitate on engagement and when I revved it up it kind of jumped in to reverse. On the other hand I tried it in the driveway when she first mentioned it and it engaged over and over without any problem.?? Of course she is afraid that she will get into a parking spot and won't be able to back out. I can understand that.

I checked the fluid level and it was up to full and the fluid doesn't smell burnt to me.

She did say that the gear selector doesn't always seem to engage exactly as it should everytime, that would indicate a linkage problem to me.

Now I've also read where the MAF sensor can cause a problem where the computer does not see sufficient flow and will result in delayed shifts. Has anyone else heard of this?? It would seem that it would cause problems in the forward gears as well which doesn't seem to be a problem. Also I am not seeing a check engine light either, which I would think if there was a problem with the MAF, it would come on.??

This is a 1999 Venture with a 3.4 L V-6 engine. It has approximately 108 K miles. Thanks for your input.
 
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  #2  
Old 06-01-05, 10:03 PM
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Most of the external sensors are used by the trans usually to control the shift point in forward during normal driving. I'm not sure about the MAF sensor but usually sensors like the throttle position sensor and vehicle speed sensor are used to determine when to actuate the shift valves. For example when pushing the gas pedal down the upshift is delayed in order to build up power.

Reverse is probably controlled purely by the manual valve in the valve body so the reason I can think of why you may be having this problem is either a linkage problem as you thought or a plugged up passage in the valve body. It could also be a sticking servo or piston. If it is a linkage problem moving the shift lever should free it. If it jumps into gear when you rev it is more likely to be internal to the trans

I think a good starting point would be to change the fluid and filter and see if this helps.
 
  #3  
Old 06-02-05, 05:26 PM
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Thanks Rav for your input. Yes, I was considering doing a filter and fluid change because I have no idea when any maintenance was done as we bought this van used a couple of years ago, but, haven't had any real major problems so far.

There is a place called "Cottman's" near here that will do a free transmission check. Probably hoping to reel in some business afterwards. But, with the cost (free), I figure what the heck, give it a try.

I know with the cost of transmission repair I'd probably be better off just finding a used tranny from a junkyard, than to get it fixed. They're pretty complex from what I've read.

I'll take a look at the linkage this weekend and see if that nets me anything.
 
  #4  
Old 06-02-05, 10:37 PM
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Hopefully the problem is minor. Unfortunately transmission repair is expensive - not sure why since they are not really that complicated to work on. Getting one from the junkyard should be cheaper but also carries more risk - it could die one day after getting it or it could run fine for years. With a complete rebuild at least all parts that are failing can be replaced. However, it is the expensive option.

The "free" check is also a good option. It may be worth seeking out more trans repair places and getting more quotes and also seeing if their diagnosis match.

This is what I would suggest you do to investigate this.

1. Change fluid and filter. It may also be worth adding a friction modifier such as "Lubegard Red" - it has helped me in the past. This product can help free sticky parts.

2. Also investigate the linkage. See if anything is binding the cable assembly and also see if when the problem happens whether wiggling the shift level helps. If only revving it helps then the problem is more likely to be internal to the trans.

3. Purchase the service/rebuild manual for you trans. You can buy it from a place like the transmission exchange co (www.txchange.com). They also have a cross ref based on car model and year what the trans model is. A good book to buy would be the ATSG manual. Their web site is www.atsgmiami.com.

4. When you take it in ask them to perform a line pressure test in reverse. Check this with the value in the manual. If it is low part of the pressure regulator valve may be sticking. If not a clutch piston or band servo may be sticking.

5. If you get this far, ask the trans place to see if they can extract and service the valve body without pulling the trans (this is possible on some models. Also check the manual). If this is the case they should take this apart and clean it.

6. If this does not work then the remaining solution would be to pull the trans and see what the problem might be.

Hopefully step 1 should fix the problem.
 
  #5  
Old 06-03-05, 06:30 PM
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Hey thanks rav you have posted some good info. I'll definitely try the Lubegard to see if it helps. I'd like to tackle the repair and I'm not a bit afraid to do it, but, its the time factor again. I just can't have it off the road for an extended period of time like that. She needs the wheels and I'm not sure how long it would take to tear into it and do a proper repair.

Its too bad I really like this van. We had a Dodge Caravan before and we had quite a bit of trouble with it, paint peeling off, head gaskets, etc.. I figured I'd try a GM product this time and its been good up to now. I just wish these car companies would pay more attention to the mechanics of the vehicles and less on the frills-hideaway seats, cup holders, dvd players, gps, etc..

I'll definitely checks those links you supplied also. I may purchase a manual if it will help me make an informed decision.

Yes she is taking it in next week to have it checked and I'll take your advise and ask them to do these things you suggested to see what that nets me.

If worse comes to worse I can pull it out and change it. I have done a few and won't hesitate on this one. It is surely a crap shoot. Hopefully I can find a yard that will give me some kind of a warranty in case I pick up a bad one right of the bat. Again, Thanx.
 
  #6  
Old 06-05-05, 12:15 AM
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Good luck with the repair and hope it turns out to be simple. Just for your info your trans is a 4T65E. Apart from the repair manual for my own trans (which I have rebuilt in the past) I also have a Chilton's book on auto trans repair (general info on how trans works, testing etc). It has a block diagram of your trans and from what I can see reverse in controlled by a band/servo assembly. If the servo is sticking or servo seal is cut/damaged you may get this symtom. Unfortunately there is no further info on the hydraulics to give you other suggestions.

I would suggest buying the ATSG manual since it will help you understand what is going on. You should also be able to do some or all of the diagnostic tests to determine what may be wrong.
 
  #7  
Old 06-05-05, 07:05 AM
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Well I found the manual on E-bay for $32.69 and I'll probably get that, just for my own info.

Hopefully after the trans. check I'll have a better idea of what is going on and can make a decision on just what my next move will be.

From what I could gather I figured it was a 4T65E transmission, but thanks for confirming it. I guess a rebuild is around $1000, OUCH!!.

Anyway I'll post back when I find something out to let you know just what the problem is. Thanks again rav for your interest in my project.
 
  #8  
Old 06-18-05, 12:13 PM
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Well we checked the dealership and they want $1900 to do a remove, repair, and install. I thought that was bad enough, I tried Cottman's and they wanted $2100 to do it. I checked around and found a small tranny shop and hopefully its going in on Monday the 20th. He is quoting me about $1200, which didn't seem to bad considering what the others wanted. Normally with a cost such as this I'd just do it myself, but from what I've heard and read its quite a process on these particular vehicles. I guess you actually have to remove some of the frame to get the transmission down and out. Along with the axles and wheels, all while holding up the motor from above. No thanks!!

From talking to some mechanics they tell me that the reverse shell (stovepipe) is damaged. I guess it is quite common on these type vans. The replacement is made of a heavier steel. Of course getting this done requires removing the tranny and rebuilding it, so......

I'll post back after its done and let anyone who is interested know what happened.
 
  #9  
Old 06-18-05, 12:43 PM
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Thanks for popping back and letting us know what happened. I'm not too suprised by the prices quoted - these seem fairly typical for trans work. Based on my own experience of pulling the trans out and rebuilding - yes, a lot of the effort is in getting it out in the first place. In my case all sorts of unrelated items such as cooling pipes, exhaust, axels, battery, starter motor, air intake - just to name some had to come out first. Also, yes, typically you have to suport the engine with a support bar assemely while the trans is out.

Did you buy the manual and if so did it help in any way. Not familiar with the term "stovepipe" unless they are referring to part of the planetary gearset used in reverse. I guess the question I would have asked is how they know it is damaged (is it guesswork or something else). If it is common on these vehicles there should be a service bulletin about it - ask to see a copy of it. I would also visit while they are working on it and ask to see for yourself the damaged part in question as well as all the guts of the trans while it is out.
 
  #10  
Old 06-18-05, 05:31 PM
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Actually rav I've gotten quite a bit of info. from another auto forum. There is a guy who seems very knowledgeable about them. Evidently he's done a bit of rebuilding and has given some good advice. He referred to the reverse shell as the "stovepipe". I guess its a slang term used in the business........... WHen we went to Cottman's Transmisssion for a check, the guy there actually showed us the part that he felt was bad and it kind of does look like a pipe with a bunch of holes in it, and the one we looked at was chewed up quite a bit. He was a little surprised that we still had the forward gears.

So you have done some tranny work? Have you worked on this type of van? If so, it must have been a project. One guy on the other forum posted a list of what has to be taken off for removal and it is pretty long. It was more than I wanted to do. Not that I'm afraid to do it, its just the time that it would take me to complete it. The Wife would be without wheels for a while, no doubt.


No, I didn't end up getting the manual. Hopefully after this I won't ever need it again, (knocking on wood). If you would like the URL for this auto forum just PM me and I'll send it to you. I'd post it here and now, but the Mods. seem to get uptight real easy and I want to keep on their good side if possible.
 
  #11  
Old 06-18-05, 05:58 PM
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Yes, I rebuilt my own trans not so long ago. It lost second gear which was due to a broken band that locks the sun gear assembly in second. I have not worked on your model of trans but once you work on one you find they are all similar (just like anything else). Yeah, I figured the term is probably used by those in the business. I'm still not sure what that term means although my best guess would be the term for the reverse servo. Yes, please PM me the link - I will addd it to my list of useful links in case I need help with something else one day.

I do agree that tackling this kind of work does require time and patience and like anything is slow the first time you do it. In order to get the trans out you have to support the engine with the support beam, lower the the whole engine/trans assemble and slide the trans out. I did buy a trans jack adapter which also can be rotated - without this supporting the 150+ pounds trans would have been difficult.

Once it was out fixing it was pretty easy. I personally think that the difficulty level to work on transmissions is made out to be much more complex than it really is. You do need to spend some time understanding how they work although strangely enough you don't really have to know this to rebuild.
 
  #12  
Old 06-19-05, 07:09 PM
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Yes, I agree about the level of expertise. I find thats true with many things. Once you've been through a couple, its no big deal. I guess its just the lack of knowledge that they can use against you. The vast majority of people have not had any transmissions projects to do over the weekend, I don't think.

This "stovepipe" looks like a hollow tube about 6" in diameter and is perforated with holes and has gear teeth made into the end of it. It looked to be around 8 or 10" long I'd say. They tell me the newer ones are made heavier.

As for the necessary tools to do it I have most of the hand tools, but I don't have a garage nor do I have the support bar and jack either. So if we end up with a stretch of rainy weather, I'm in trouble out in the driveway.


I called the guy who is going to do the work on the van and he has put me off for another week. I guess he has one more tranny ahead of him. I hope he isn't jerking my chain and is true to his word. I've had several people vouch for him, so I'm thinking he will come through. Its just a matter of time.

I will send you the link right after I close this one out.
 
  #13  
Old 06-20-05, 10:46 PM
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Yes, that sounds to me like some part of the planetary gear system. From what I saw of your trans (the diagram in my book is rather poor) reverse is created by a brake rather than a clutch so the drum you saw is probably the section that locks in reverse. The thing about planetary gearsets is that they work as a unit so the person who was suprised that your van was still running is correct. If that part actually breaks you will most likely lose all gears.

As for tools - yes you will need a few special tools depending on your trans. In my case I had to get an oil pump puller and a clutch pack compressor. Also got a servo compression tool but did not have to service the only servo the trans has. Tranny tools tend to be expensive but used tools are a good option (good selection on ebay). But, yes, having no garage kind of rules out working on it yourself.

Given the fact that you have the problem only in reverse I personally would have suspected something connected with the hydraulics or servo but I guess it should come to light during the rebuild.

I did find your discussion thread on the other forum and I see he did not answer your last question about the oil pan. Sometimes people install deeper aftermarket oil pans. This reduces the possibility of oil starvation during heavy load and also better cooling since the volume of oil is higher. You may want to consider it if your van is used in extreme conditions. The other thing is that some come with oil drain plugs whereas the factory fitted ones may not (mine has it luckily).

The list of items quoted that needs to come out looks familiar give or take a few things.
 

Last edited by rav12; 06-20-05 at 11:14 PM.
  #14  
Old 07-04-05, 06:15 AM
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Just a quick note particularly to Rav12. We did finally get the van to the tranny guy on Wed. the 29th, although it took a while to actually find the place, (that's another story). This is a really small operation with only a couple of bays. I can see why it takes him a while to turn his repairs over. But, I guess thats why his costs are lower.

I'll post back with the results of the repair job when we get it back. Meanwhile here's wishing you and yours a Happy and Healthy Fourth of July.
 
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Old 07-09-05, 07:21 AM
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Just wanted to close this one out and to say that the Chevy van is back on the road again. The bill was only about $1000, so it wasn't as bad as I thought it might be. The tranny guy had to replace alot of parts in there, such as the high speed clutch hub, all electronic solenoids (which he said were not necessarily bad, just should be done while in there), torque convertor,pressure modulator, pwm solenoid, shift solenoid, epc motor. It was almost $600 in parts alone.

Overall I'm glad I didn't attempt this repair. I think it was more than I wanted to do and I feel that I am pretty handy on the whole. I recommend that the majority of owners of this particular van take it to the shop if they need a similar repair job done.

Oh, I almost forgot to say, he also told me that this transmission already has had a remanufacture done in the past and that the reverse shell already had the updated part in it. I guess this gives an indication of the quality of the parts or that who ever owned it previously might have towed with it.
 
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Old 07-09-05, 11:10 AM
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Good to hear that everything is back to normal and that it is working well. Thanks for coming back and updating us on how it went. I'm still curious as to what the real problem was. As I suspected it was not the reverse shell as was suggested by the tranny guy in the other forum. It seems like he replaced all posible parts that could be the cause. It is unlikely they were all faulty. To me the most likely causes could have been the modulator system or one of the solenoids. The torque conveter replacement seems unecessary.

At least the labor charge seems reasonable. I can believe that all the parts listed would easily come to the total you have mentioned. Yes, there is some truth in the argument that while it is out replace everything thay could go faulty and save the headache in the future.
 
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Old 07-10-05, 03:58 AM
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Hello rav, stupid me thats the one thing that I forgot to mention in my closing post, thanks for reminding me. He said that there was a gasket or an o ring that was blown out in some channel and it was causing whatever makes the reverse engage, to not engage. Sorry for being so vague, but thats about all he told me about that.......He seemed to be more concerned about the 4th gear hub being worn out than anything else......Yes, replacing the torque convertor did seem odd to me also and I raised that question to him and he just said that it needed to be done. I know the price of it on the receipt was $135, which was the most expensive item. The hub was $75.47, and there was another part, which I am not sure what it is, a K66900H hit, it was $83. Its hard to read his writing where he tends to scribble, something like a doctor does........Anyway thats about it for that project. Now I'm waiting for the rain to stop so I can finish my windshield job. I had the windshield guy take the windshield out of my old Subaru and I'm trying to clean up the rusted areas around the edges and paint it up so it will be nice and smooth when he installs a new one. Of course without a garage, this makes it a little tougher to do. Oh well, maybe someday.
 
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Old 07-10-05, 11:10 AM
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OK that makes sense - a cut seal or gasket would definitely cause this kind of symptom. This thread is now quite long but as I recall from earlier your trans uses a band to engage reverse and a cut or damaged seal in the reverse servo could cause this - in fact I believe I did mention that in an earlier posting. Most likely that would have been it.

Overall it sounds like the whole thing went well and hopefully that's the end of your tranny problems for now. I agree - not having a garage does rule out being able to work for extended times on projects (cars and other things).
 
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