After letting my car sit in the garage for a month in disgust... I need to pull the trans again. I know it will be obvious when its pulled but i was wondering if someone might know just from this description....

Car is in OD... 25mph WOT down shift to first, tires spin and hook (315s), once it hits 2nd gear it felt like I broke my rear DS or axle. Engine RPM hit the roof and I backed off. This all happened in a split second.

After realizing my car still rolled without any noises, I proceeded to ease into the throttle.... no go... I put the trans in manual low and it works fine, 2nd gear works as well. If you put the selector in D or OD... it does not budge at any speed. Reverse is fine...

Any ideas to what went wrong?

 

Sounds like you probably grenaded the input sprag assembly !!!!!!!!!!!!!!

 

I second that.

 

You greanaded the low roller clutch , You canmove now because it comes on in low and some cars have a second gear start and will take off there . The input sprag would allow movment in dbut not od due to the overun clutch coming on ,

 

What can I do to beef up the input sprag and low roller clutch?

 

You'll need to purchase the Borg Warner updated parts.

g

 

Well... I wasn't able to find any broken parts. However after checking the valves in the VB - I noticed that the 1-2 Accumulator Valve was stuck. What problems would that have caused?

The trans needed to be torn down again anyways for a new 3-4 clutchpack. They are burned again! Probably less than 300 miles. I think the 3-2 kickdown is what is killing them. There is a solid 1.5-2 second pause before the kickdown occurs. I don't think the 3-4 piston is releasing quick enough. I don't have upgraded 3-4 return springs. Does anyone think this may be my problem?

Again, thanks for everyones help!

David

 

if you have the return springs installed, take them out,,

 

I you may be referring to the 3-4 clutch boost springs. Those have already been removed.

 

This may explain things...

 

Eh, JB weld it and put it back in.

 

What is the strongest sprag available I can replace this with? This WAS an updated B/W 29 element sprag.

 

Doesn't that normal also cause the overrun clutches to toast too?

 

It is not a double cage sprag. It is a stock type, non updated component.

Axiom pn A74658B is what you need. It is the heavy duty double cage sprag. Yours failed because it did not have the added support and the cams simply rolled over causing excessive pressure... then boom. The double caged sprag won't do that.

g

 

Axiom pn A74658B is what you need. It is the heavy duty double cage sprag. Yours failed because it did not have the added support and the cams simply rolled over causing excessive pressure... then boom. The double caged sprag won't do that.
The cage keeps the elements in place nothing more, and it does not offer support. You can collapse these cages with your hand. I have seen both blow up/roll over. I have found that the SKF to be in the vast majority of GM units and do very well, and have seen them go for well over 200,000 miles. I prefer and use the SKF's in all of my builds. Is one superior over the other?, or is one stronger than the other? Not from my experience, but each has his reasons for using either the BW or SKF. With the sprag that is the subject here, you will need to replace the entire input assembly. Check the lube circuit carefully.

 

3-4 is burning up partially due to the use of the old style 700R4 pressure plate thats paper thin.

 

IMO the SKF is a weak design. I was told at one point by a guy I was working for that it was a better sprag for various reasons. He was a huge Raybestos fan and my understanding is that the SKF applied differently because the cams were of a different design. The way in which they applied was supposed to react differently over the Borg set up and was thought to be stronger. Well I tested this piece in over a 100 units that were used in a high performance application using the Raybestos products. We had multiple failures and the owner said that abuse was the issue all along. This is where I proved my case on the sprag. I did not change anything in my build procedure other than installing the Borg set up in vehicles that we had issues with. The Borg setup lasted much longer and the units did not come back with the sprag failure. I brought this to a rep from Raybestos attention that we were doing testing for. He asked for the failed sprags so they could look to what the issues were and why they failed. This sprag worked excellent in a stock application for us but not in a performance application. We then started having issues with the pro-series bands breaking and 3-4 clutch drum breakage issues. I believe that the clutch material and band material that was being used was very abusive when applied. Allowing next to 0 slippage. The rep had absolutely no reason to offer to as why we had the failure that we had. This being said I believe that these units were being built with the wrong theories and materials, thus the failures that we had at my previous place of employment. I with FLT have taken a different direction in building theories and I believe the success rate by far exceeded my expectations. I believe in the Borg sprag and the BW products. Obviously they are not the only products that go into a build but I am very proud of what we have accomplished in the last couple of years. Vince

 

I guess that is where we differ, as I do not have sprag failures using the SKF's, believe me if I did I would change it. By the way I am not a fan of Raybestos products, as this is the only Raybestos product that I use that I aware of, otherwise I am a big user of Borg Warner clutches, band material, etc. I have always believed that what ever works best (from my experience) is to use it.

"3-4 is burning up partially due to the use of the old style 700R4 pressure plate thats paper thin."
I have not seen this, as I have used the .125" pressure plate with the .055" five finger 3-4 apply retainer in many units over the years. There many reasons for the 3-4 clutch to burn, but from my experience this is not one of them.